Header plug



Sept. 14, 1943. M. L, MOSHER HEADER PLUG Filed March 26 1942 Hiim neyPatented Sept. 14,1943

HEADER, PLUG Merritt L. Mosher, Philadelphia, Pa., assignor to TheAtlantic Refining Company, Philadelphia, Pa., a corporation ofPennsylvania Application March 26, 1942, Serial No. 436,258

Claims.

The present invention relates to removable closures for furnace tubeheaders or return bends. and more particularly to improvements in plugsassociated with tube headers utilized at high temperatures and pressurescommonly encountered in oil cracking and refining operations.

An object of this invention is to provide an improved plug for tubeheaders adapted to be attached to the ends of adjacent tubes, the plugbeing so constructed that it wil1 withstand the high temperatures andpressures to which it is subjected when in use, and at the same timeprovide a leak-proof Joint.

A further object of this invention is to provide an improved plug fortube headers adapted to be readily inserted or removed from the headeras necessity demands, the plug being so constructed as to adapt itselfto the plug seat, irrespective of slight changes in the dimensions orshape of the seat which norm-ally occur during use.

Other objects of the present invention will be readily apparent from thefollowing description, reference being had to the accompanying drawingwhich shows a side sectional elevation of one embodiment of theinvention.

Referring to the drawing, I represents the body of the tube header,recessed at 2 to accommodate the end of furnace tube 3 which is lockedin place and sealed by expansion into grooves 4 of the header. Passage 5communicates with the other half of the tube header corresponding to I,which, being of identical construction, is not shown. The ,upper portionof the header body I is provided with a tapered plug seat 6 adapted toengage the tapered plug 1, such plug comprising a truncated conical body8 provided with a stem 9 carrying a nut III, and being counterbored orrecessed at II to impart a certain degree of flexibility to the taperedside wall of the plug body. The upper inner margin of the plug is groundor machined to provide a bearing surface I2, preferably spherical orconcave, for the thrust ring I! which is apertured centrally at It toaccommodate stem 9 of plug 1. The upper and lower surfaces of the thrustring are ground or machined to conform substantially to the curvature ofthe bearing surface I2 of the plug, and the bearing surface I5 of theset collar I5, respectively. By utilizing a thrust ring having twospherical bearing surfaces, it is possible to obtain an excellentadjustment between the set collar I6 and the plug I, and to equallydistribute the pressure over the plug seat 6. The plug 1, beingcounterbored at II for flexibility, is more easily distortable than asolid plug, and readily accommodates itself to the shape and angle ofthe plug seat 8, thereby producing a tight seal.

The upper portion of the header body I is recessed and threaded at H,and is adapted to engage the threaded portion of the set collar I6, thecollar being provided at its upper periphery with a plurality ofvertical, flat faces I 8 to which a wrench or spanner may be applied fortightening. The set collar is further provided with a central recess orbore I 9 through which the stem 9 of plug 1 projects.

In operation, the assembly comprising the plug 1, thrust ring I3, andthe set collar I6 is inserted in the header body I, the plug 1 engagingthe plug seat 6. The set collar is screwed into position and tightenedby means of a wrench or spanner applied .to the flat faces I8 of thecollar,

the pressure due to tightening being transmitted through the thrust ringI3 to the sperical surface I2 of the plug body 8. Due to the sphericalshape of the thrust ring surfaces and the upper inner margin of the wallof the plug, the pressure from the set collar is directed bothdownwardly and radially outwardly in such a manner that the plug I isfully seated, and the flexible walls of the plug are urged radiallyoutwardly into tight contact with the plug seat 6, thus producing aleak-proof seal.

In the event that it becomes desirable to open the header I forinspection or cleaning of the interior surfaces of the tubes, the setcollar I6 is unloosened by means of a wrench, thereby relieving thepressure upon the thrust ring I3 and the plug 1. The plug, if too firmlyseated, may be loosened by light blows from a maul applied to the stem9, and the plug assembly may thereafter be removed from the header body.

I claim:

1. In combination, a tube header body having an aperture therethroughprovided with a tapered seat and a threaded portion extending from thewide end of said seat, a tapered plug engageable with said seat andrecessed to provide a distortable side wall, the upper inner margin ofwhich has a contour adapted to transmit pressure downwardly and radiallyoutwardly, a thrust ring having upper and lower spherical surfaces, anda threaded collar adapted to engage the threaded portion of said headerbody, said collar having a lower inner portion with a contour adapted toengage the upper spherical surface of said thrust ring.

2. In combination, a tube header body having an aperture therethroughprovided with a ta-- pered seat and a threaded portion extending fromthe wide end of said seat, a tapered plug having a stem integraltherewith and extending axially thereof, said plug being engageable withsaid seat and recessed to provide a distortable side wall, the upperinner margin of which has a contour adapted to transmit pressuredownwardly and radially outwardly, a thrust ring centrally apertured toaccommodate said stem and having upper and lower spherical surfaces, anda threaded V collar adapted to engage the threaded portion of saidheader body, said collar being centrally recessed to accommodate saidstem and having a lower inner portion with a contour adapted to engagethe upper spherical surface of said thrust ring.

3. A removable closure for tube headers and the like, comprising atapered plug having a stem integral therewith and extending axiallythereof, said plug being recessed to provide a distortable side wall,the upper inner margin of which has a surface contour adapted totransmit pressure downwardly and radially outwardly, and a thrust ringoverlying said plug having an under surface complementary to the surfacecontour of the upper inner margin of said wall, said ring beingcentrally apertured to accommodate said stem.

4. A removable closure for tube headers and the like comprising atapered plug recessed to provide a distortable side wall, the upperinner margin of which has a surface contour adapted to transmit pressuredownwardly and radially outwardly, a thrust ring overlying said plughaving an under surface complementaryto the surface contour of the upperinner margin of said side wall, and means operatively engageable withsaid thrust ring to distort said side wall.

5. A removable closure for tube headers and the like comprising atapered plug recessed to provide a distortable side wall, the upperinner margin of which has a spherical surface adapted to transmitpressure downwardly and radially outwardly, a thrust ring having upperand lower spherical surfaces, the lower of said spherical surfaces beingcomplementary to the spherical surface of the upper inner margin of saidside wall, and screw means operatively engageable with said thrust ringto distort said side wall, said means having an under surfacecomplementiiiry to the upper spherical surface of said thrust r ng.

MERRITT L. MOSHER.

